Secrets of soil unearthed

A £1 million project has begun to investigate the way organic carbon, in the form of compost or manure, can affect the way soil behaves.

The research is a collaboration between the University of Abertay Dundee's SIMBIOS centre, the Institute of Arable Crop Research, and consultancy firm ADAS.

Professor Iain Young, director of the SIMBIOS centre, will be leading a team looking at the ways in which the biophysical and biochemical properties of soil are affected by the fungi living within it, while the partner institutions will be looking at the practical applications of that knowledge to land management techniques.

Meanwhile, seven sites across the UK are conducting field trials looking at how different soils react to varying additions of organic carbon.

"Degradation of the soil becomes most likely when the proportion of organic carbon in the soil drops below 2%, but we don't know exactly how the carbon interacts with the bacteria and fungi that live naturally in the soil," said Professor Young. "We can't therefore predict how manipulating the carbon content by adding compost or manure will affect the long-term sustainability and productivity of the soil."

He added that every handful of soil contains thousands of different species of bacteria and fungi, interacting with each other and with their immediate environment, according to their own requirements.

"We need to know much, much more about these interactions and how they are influenced or interrupted by human activities such as adding compost, moisture or chemical fertilisers," said Young.

"In short, we know that adding organic carbon to soil is good for it but we don't know exactly why."

The need for answers to such questions is becoming increasingly urgent as growing populations put pressure on food supplies, and, therefore, on the planet's limited stock of fertile soil.

Mistreating soil through intensive farming and over use of chemicals can eventually the sort of dustbowls that almost destroyed US agriculture in the 1930s, and which have devastated parts of northwestern China and Inner Mongolia in the last five years.